New Rocket Schem

[benoit]

I just whacked together a rocket schematic by cutting and pasting Mark Abbott's Rocket preamp drawing to his Liverpool power amp and power supply. Any glaring errors, omissions?

I'm pretty sure the 22k/8uf, 10k/32uf pairs of caps and resistors are meant to be the power supply dividers and filter caps. Since there are 2 22k and 1 10k b+ resistors I'm guessing its 2 22ks on the 12ax7s and the 10k for the screen grids. Or is it the 22k resistors for the screen and the 2nd stage and cathode follower, and the 10k for the first stage? Further adding to the confusion mark states that the filtering for the el34 plates is likely 80uf, which is the same as the liverpool value. He also says post 160 claims that same filter cap is 2 220uf caps in parallel. I'm very confused. Anyway, here's the schematic, take a look and tell me what you think.


Ben

[nickt]

Hi Ben,

Don't know much about wrecks but know a little about AC30s. Marks schematic I think already includes most of the PS except for the tranny, rectifier and the "pi" filter (two caps and choke). The funny thing about AC30's is the PI/PA filtering comes off the screen side of the "pi" filter as a star rather than in series.

No idea what effect this has on sound however or if KF did it that way!!

Hope this helps.
Nick

[riscado]

you do realize that there are complete schematics already, don't you?

[benoit]

Riscado, the only complete schematic I found is Matt Taylors. Matt's is NOT in the files section. Mark's IS. I assumed there was a reason for this. There is only one rocket schematic in the files section, and I mentioned in the thread here: https://tubeamparchive.com/viewtopic.ph ... highlight= that the only other info I could find was paul's layout.

That said, if there are complete schematics around please, point me in the right direction. I have spent hours and hours of time I don't have combing the forum

[riscado]

What's the problem with Matt's schematic, it look very nice too me...

if it's not in the files section, well put it there!

[nickt]

What's the problem with Matt's schematic, it look very nice too me...

if it's not in the files section, well put it there!

Matt's schematic is at variance with Mark's hence confusion - particularly to newbies like myself.

[benoit]

What's the problem with Matt's schematic, it look very nice too me...

if it's not in the files section, well put it there!

It wasn't that there was anything so WRONG with Matt's schematic, you're right that it looks nice.

My frustration was that I could not seem to nail down one single rocket that was as close as possible to the original. The best info I got on that was mate mark abbott's pre to the liverpool power section. Paul ruby, on the other hand, says mate mark's pre to the 36w power section from 18watt.com, without the NFB, with 1k5s on the grids, and with mark's filtering scheme. That put's me in a good spot in that now I have a complete schematic to work with that meshes reasonably well with paul's layout, which will make the build process a lot simpler. I'm still not quite satisfied. Lots of people have their own take on a rocket that works, but no one seems to be able to say definitively "This is exactly how one real rocket was built." I'm not going to get too hung up on that to get a build going, though.

Ben

[riscado]

believe me when I say Matt's schematic is accurate enough...